1. Field of the Invention
The present invention relates to a binding apparatus, and in particular relates to a binding apparatus that is connected with a sheet discharging part of an image forming apparatus, such as a printer and a copier, and that folds a sheet received from the image forming apparatus and binds stacked folded sheets at the folded side parts of the folded sheets.
2. Discussion of the Background
A binding technology used in producing weekly magazines is well known. After printed sheets are stacked and jogged, the stacked printed sheets are stapled at their center portions by a stapling device. The stapled sheets are then folded at their stapled portions. Because the stapled sheets are folded at their stapled portions, the side edges of the folded sheets, opposite the stapled and folded side of the folded sheets, are not uniform. Therefore, the side edges of the folded sheets, opposite the stapled and folded side, are cut off by a cutting apparatus so as to be uniform.
A binding apparatus is known to be connected with a copying machine, downstream of a sheet discharging part of the copying machine in the sheet discharging direction. The binding apparatus sorts or collates sheets carrying an image on one or both sides of the sheets, which have been discharged from the copying machine, and then jogs and binds the sheets into a stack of sheets.
In the binding technology used in producing a weekly magazine, as described above, the side edges of the folded sheets, opposite the stapled and folded side of the folded sheets, must be cut off by a cutting apparatus so as to be uniform. Noise is produced when the side edges of the folded sheets are cut off by the cutting apparatus. The cutting apparatus is relatively large, heavy and expensive. The life of a knife used in the cutting apparatus is relatively short. Further, the consumption of electric power is relatively large. When the number of printed sheets, which must be folded, is large, the folding apparatus may not sufficiently fold the sheets.
A binding apparatus used in conjunction with a copying machine generally stacks sheets, which have been received from the copying machine, without folding each of the sheets, into a stack of sheets, and then staples the stacked sheets. The stacked sheets are stapled at edge portions of the sheets at one side. Therefore, when a sheet of the stack of stapled sheets is pulled, the stapled part of the pulled sheet is easily torn, so that the pulled sheet is taken apart from the stack of stapled sheets. For avoiding this problem, the stapling position for a stack of sheets must be located well inside of the stack of sheets toward the center portion thereof. This may result in stapling the sheets at a part of the image area of each sheet, so that the inconvenience may be caused such that a part of the image at the stapled part of each sheet cannot be seen. For avoiding the inconvenience, the image must be formed on each sheet with a relatively large margin for stapling, which then reduces the area in each sheet where an image can be formed.